Department of Pharmacy, College of Pharmacy, Mokpo National University, Muan 58554, Republic of Korea.
Department of Pharmacy, College of Pharmacy, Mokpo National University, Muan 58554, Republic of Korea; Department of Biomedicine, Health & Life Convergence Sciences, BK21 Four, College of Pharmacy, Mokpo National University, Jeonnam 58554, Republic of Korea.
Phytomedicine. 2022 Oct;105:154383. doi: 10.1016/j.phymed.2022.154383. Epub 2022 Aug 3.
Isolinderalactone (ILL), a sesquiterpene lactone compound, can be extracted from the root of Lindera aggregate. Physiological activities of ILL, including anti-inflammatory and anti-proliferative effects, have been investigated in multiple diseases. Nevertheless, little is known regarding its anti-cancer activities and the mechanism of action of ILL in targeting human CRC cells.
To determine ILL-mediated anti-proliferative effects on oxaliplatin (Ox)-sensitive and resistant colorectal cancer (CRC) cells and underlying mechanisms involved in its effects focusing on signal transduction.
Inhibitory effect of ILL on CRC cells was evaluated by analyzing mitochondrial membrane potential (MMP) dysfunction and multi-caspase activity. Apoptosis-regulating proteins and JNK/p38 signaling molecules were monitored by Western blotting. ROS-dependent physiological modifications by ILL were confirmed by pretreatment with N-acetylcysteine (NAC). Moreover, the involvement of JNK/p38 signaling in ROS-mediated apoptosis was verified by treatment with SP600125 (JNK inhibitor) and SB203580 (p38 inhibitor).
ILL decreased cell viability and colony formation in both CRC Ox-sensitive (HCT116 and HT29) and Ox-resistant (OxR) (HCT116-OxR and HT29-OxR) cells. ILL induced G2/M phase cell cycle arrest, ROS generation, phosphorylated (p)JNK/p38 MAPK activation, mitochondrial membrane potential (MMP) depolarization, and multi-caspase activation, which eventually triggered apoptotic cell death of CRC cells. In addition, combined treatment with ILL and SP600125, SB203580, or pan-caspase inhibitor (Z-VAD-FMK) prevented decreases in cell viability seen after treatment with ILL alone. Pretreatment with NAC attenuated ILL-mediated apoptosis, ROS production, and p-JNK/p38 expression.
Taken together, our results suggest that ILL can exert its anticancer effect in CRC Ox-sensitive and OxR cells by inducing ROS-mediated apoptosis through JNK/p38 MAPK signaling pathways. This is the first study demonstrating that ILL has a potential to improve drug efficacy against resistance mechanisms, providing a new insight into therapeutic strategies targeting drug-resistant CRC.
异土木香内酯（ILL）是一种倍半萜内酯化合物，可从土木香根中提取。ILL 的生理活性，包括抗炎和抗增殖作用，已在多种疾病中得到研究。然而，关于其抗癌活性以及 ILL 靶向人 CRC 细胞的作用机制知之甚少。
确定 ILL 对奥沙利铂（Ox）敏感和耐药结直肠癌细胞（CRC）的增殖抑制作用及其作用机制，重点关注信号转导。
通过分析线粒体膜电位（MMP）功能障碍和多半胱氨酸酶活性来评估 ILL 对 CRC 细胞的抑制作用。通过 Western blot 监测凋亡调节蛋白和 JNK/p38 信号分子。通过用 N-乙酰半胱氨酸（NAC）预处理来确认 ILL 引起的 ROS 依赖性生理变化。此外，通过用 SP600125（JNK 抑制剂）和 SB203580（p38 抑制剂）处理来验证 JNK/p38 信号在 ROS 介导的细胞凋亡中的作用。
ILL 降低了 CRC Ox 敏感（HCT116 和 HT29）和 Ox 耐药（OxR）（HCT116-OxR 和 HT29-OxR）细胞的细胞活力和集落形成。ILL 诱导 G2/M 期细胞周期停滞、ROS 生成、磷酸化（p）JNK/p38 MAPK 激活、线粒体膜电位（MMP）去极化和多半胱氨酸酶激活，最终导致 CRC 细胞的凋亡性细胞死亡。此外，用 ILL 和 SP600125、SB203580 或泛半胱氨酸酶抑制剂（Z-VAD-FMK）联合治疗可防止单独用 ILL 治疗后细胞活力的降低。用 NAC 预处理可减弱 ILL 介导的凋亡、ROS 生成和 p-JNK/p38 表达。
综上所述，我们的结果表明，ILL 通过 JNK/p38 MAPK 信号通路诱导 ROS 介导的细胞凋亡，在 CRC Ox 敏感和 OxR 细胞中发挥抗癌作用。这是第一项表明 ILL 具有提高药物对耐药机制疗效潜力的研究，为针对耐药 CRC 的治疗策略提供了新的见解。
